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Precision with MPXA6115A for an altimeter application

Question asked by Baptiste THOMAS on Feb 16, 2016
Latest reply on Feb 16, 2016 by David Diaz Marin

Hi,

I plan to use the MPXA6115A for an altimeter application. This device is suggested in the datasheet for this kind of application.

When I calculate altimeter precision from the datasheet, result is very bad.

Sensor is given for +/-1,5%, for my application I've to apply a temperature factor of 2,5, so for the full scale of pressure the accuracy is +/-3,75%.

+/-3,75% corresponds to a +/-37,5hPa.

The range of the altimeter I hope to do is from 0 to 2000m correspondig to a pressure of 1013,25 to 800 hPa (only a part of the sensor range).

On this range, altitude and pressure could be considered as linear.

I want to detect a 1100m threshold corresponding to 888hPa.

888hPa +/- 37,5hPa corresponds to about 1100m +/-350m. Error I can have on the sensor impact considerably the altitude.

To have a good accuracy on altitude, is it necessary to calibrate the sensor ? if YES, what do you advice ?

What solution exist to reduce this error and how this error is divided (offset, linearity, hysteresis, offset drift with temperature, linearity drift with temperature...)?

I hope to have an accuracy of about +/-20m (worst case +/-50m)

I know that digital sensor exist with a better accuray but analog sensor must be used in my application.

 

Best regards

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